session cookie/login problem

[Gasolene]

I have a login that sets a cookie.

$barney = "A big purple dinosaur.";
session_register("barney");

all pages check for this cookie.

session_start();

if( !($_SESSION["barney"] ))
{
// redirect...
}

I can login fine with my own PC, or the one at work.
But I can't login with my clients PC.

I have disabled ALL privacy settings, anti-virus, firewall, ect...

I have also tried other PC's here (all in same network).
can the router block cookies??

note: I can access webmail and other login systems.

[rachel2004]

Instead of:

session_register("barney");

Use:

$_SESSION['barney'] = "a big purple dinosaur";

Also, try doing a check of $_SESSION['barney'] to see if it contains a value:

echo $_SESSION['barney'];